GPX4 degradation contributes to heat stress-induced liver injury via chaperone-mediated autophagy

Heat stress (HS) is a significant health concern that adversely affects both human and animal health, particularly impacting liver function due to its central metabolic role. This study investigated the mechanisms underlying HS-induced liver injury, focusing on the role of ferroptosis, an iron-dependent form of cell death characterized by lipid peroxidation and cellular iron accumulation. Using mouse and cellular HS models, the results demonstrated that HS induced liver injury through ferroptosis, as evidenced by increased levels of malondialdehyde (MDA), oxidized glutathione (GSSG), and iron, alongside decreased glutathione (GSH) and glutathione peroxidase 4 (GPX4) expression. The ferroptosis inhibitor Ferrostatin-1 (Fer-1) effectively mitigated HS-induced liver damage, reducing oxidative stress and restoring GPX4 levels. Furthermore, HS promoted the lysosomal degradation of GPX4 via the chaperone-mediated autophagy (CMA) pathway, which was regulated by heat shock cognate protein 70 (HSC70) and lysosome-associated membrane protein 2A (LAMP2A). Knockdown of LAMP2A in hepatocytes significantly suppressed HS-induced GPX4 degradation, confirming the critical role of CMA in this process. Inhibition of CMA using Apoptozole, an HSC70 inhibitor, or Bafilomycin A1 (Baf-A1), a lysosomal inhibitor, further attenuated HS-induced ferroptosis and liver injury. These findings highlight the critical role of CMA-mediated GPX4 degradation in HS-induced ferroptosis and liver injury, providing potential therapeutic targets for mitigating HS-related liver damage.